612 PHOCEEDIXGS OF THE TIIIED ENTOMOLOGICAL MEETIXG 



The nyniplis as -well as the females prefer to feed on the tender apical 



leaves of mulberry plants. In order to determine when and how the 



malformation of the mulberry shoots was caused a newly-hatched nymph 



was taken and put on a healthy growing bush-mulberry cutting in a 



pot. The nymph was transferred on the plant on 4th September 1916 and 



on 12th September 1916 the place where the nymph had fixed itself to 



feed in the axil of a leaf had turned deep coppery-green and the stem 



flattened out laterally. Soon after the presence of the nymph on the 



plant could be known easily by the presence of the ant, Monomorivm 



indicum. The ants attend upon the nymphs and the maturing females 



for the sake of the honey-dew. They have not been seen to attend 



upon the full-grown male nymphs prior to their pupation. They have 



also not been seen to attend upon the gravid females when they have 



begun laying eggs and are covered with fine, whitish cretaceous threads. 



eispecially towards the pygidial end. On the 18th September 1916 



the leaves had curled distinctly and had turned deep coppery-green. 



The characteristic malformed head was formed and the leaves forming 



these had changed colour and had become firm and crisp. The following 



day one or 'two patches of the mulberry mildew, PJiylladinea corylea, 



were visible on the leaves. The plant on to which the nymphs were 



transferred had remained immune from the attack of the fungus, along 



with another plant potted at about the same time as this, but now began 



to show traces of the presence of the mildew. It was just possible. 



because the vitality of the plant was lowered by the undue draining" 



away of the sap which would have gone ordinarily to the development 



and maturing of the plant, that the mildew appeared. _ The other plant 



was also unfortunately utilized for marking the development of the apical 



malformation, otherwise if it had been kept separate it would have served 



well for comparison. On the 23rd September 1916 I talked this over 



with Dr. E. J; Butler, Imperial Mycologist, Pusa, and he very kindly 



gave me access to literature* belonging to him, wherein it was recorded 



that the plants at first immune from the attack of a fungus fell a victim 



to it as soon as they became infested with tAphididse. . The experience 



gained by me was very much similar to this. Early in 1909 when the 



mulberry leaf-mildew was very prominent on a few plants- in a small 



plot of broad-leaved mulberry plants in the compound of the bungalow 



occupied by Mr. H. Maxwell-Lefroy, I found a large number of grubs 



and adults of Then cincta, feeding voraciously on the mildew on leaves. 



* I. On Erysipjiis graminis, Dc. and its adaptive parasitism within the genus Bromvs 



Ernest S. Salmon, F.L.S., (Annales Mtjcologi, Vol. II, Nos. 3 and 4, 1914, pp. 24-25). 



2. Cultural experiments with " Biologie Forms " of the Erysiphaceoe Ernest 



S. Salmon, F.L.g. {Phil. Trans. Boyul Soc. .London, Series B, Vol. 197, p. 112). 



